Furnace



H. A. STEWARTA Jan. 2.6, 1937.

FURNACE Filed Jan. 5, 1955 2 Sheets-Sheet l @mul INVENTOR Jan. 26, 1,937.

FURNACE Filed Jan. 5, 1935 2 Sheets-Sheet 2 /ENTOR j gyMmmM/m Patented Jan. 26, 1937 UNITED STATES PATENT OFFICE 2 Claims.

My invention relates to furnaces, and is hereinafter described as employed in a combined gas and coal domestic heating furnace of the hot air type, but it will be understood that various fea- 'tures of the invention could be employed also in other types of furnaces.

One object of my invention is to provide a furnace of simple and compact form, wherein it is possible to burn either coal or a lighter fuel, suc as gas or oil.

Another object of my invention is to provide a combination furnace of the type referred to wherein no rearrangement or changes of parts are required when changing from one type of fuel to another type.

One form which my invention may take is shown in the accompanying drawings wherein Figure 1 is a side View of the furnace, partially in section; Fig. 2 is a front elevational view thereof; Fig. 3 is a view, on an enlarged scale, taken on the line III-III of Fig. 1; Fig. 4 is a vertical sectional view taken at right angles to the View of Fig, 3; Fig. 5 is a View taken on the line V-V of Fig. 1, and Fig. 6 is a sectional view similar to Fig. 3, but showing a modification.

The furnace is shown as having a hot air jacket 8 which may be of any suitable Well-known form, provided with the usual air inlet near its bottom, and with the hot air outlets 9. The jacket 8 encloses a smoke box or radiator I3 through which smoke or gases of combustion are passed, the smoke or burnt gases entering in through a flue II and passing down beneath a baffle plate I2 through a flue I3. The smoke box I has openings at its lower side, so that it can be readily cleaned, the openings being normally closed by doors or caps I 4 that extend through the sides of the jacket 8.

Within the jacket 8 is mounted a nre box casing I5 of generally rectangular form, smoke from the re box being discharged through a flue I6 to the flue II of the smoke box I0. The nre box is set against the front Wall of the jacket 8, and is provided with the usual fire door and ash pit openings, which openings also extend through the front wall of the jacket 8. Castings or face plates I1 and I8 are provided at the front of the furnace, and suitably secured thereto, as by rivets or bolts.

A fire door I9 of any suitable form is mounted on the casing I1 and an ash pit door 2| is mounted on the casting I 8. A pair of partition-like members 22 are mounted on the bottom wall of the casing I5 and serve as side walls for the ash pit. At their upper ends, the partition members 22 have channels 22a formed therein, as shown more clearly in Figs. 2 and 3, for supporting bars 23a in which are journalled oscillatory grate bars 23. The grate bars have connection with a lever 24 (Fig. l) that is operated from the front of 5 the furnace by a link 25 and a bell crank 26, in a well-known manner.

Fire bricks 27 or other suitable lining material is supported on the channels 22a at the sides of the furnace, and a rear lining 28 is supported in 10 crosswise relation upon the rear ends of the channels. A front lining 28a is provided to protect the front Wall of the flre box casing I5.

The ash pit door 2I has a draft door 29 to which is connected a lifting chain 3| that is operated 15 from a rock shaft 32. A pull chain 33 is connected at its lower end to a crank 34 that is carried by the rock shaft 32, and at its other end to suitable well-known automatic regulating mechanism, so that the draft door 29 may be 20 opened and closed in accordance with desired draft conditions.

The shaft 32 also carries a pair of cranks to which lifting chains 35 are connected, said chains also having connection with draft doors 36 that 25 control ow of air to gas combustion chambers as hereinafter explained.

Between the partitions 22 and the side walls of the fire box I5, I mount gas burners 31 which are provided at their outer ends with the usual air mixers 38. These burners are isolated from the ash pit and the grate bars by the partitions 22, so that they are in no danger of becoming clogged with ashes. The fire brick linings 21 are disposed mainly in spaced relation to the .side Walls of the furnace casing I 5, so that gas flames can pass up through the spaces 48, and over the tops of the walls 21 into the upper portion of the fire box from which the burnt gases are discharged through the flue I6. Heat will be radiated from the side walls of the furnace I5, and thus heat the air which is passing through the jacket 8. Spacing elements 4I are provided on the fire bricks 2'1, that serve not only to preserve the spaces 40, but may become heated to incandescence, and thus facilitate the combustion of the gas or other light fuels, as in the case of radiant heaters.

Ordinarily, coal and gas will not be burned at the same time, but it will be seen that they can 5o be selectively employed without making any changes whatever in the furnace, and that the same regulator chain 33 may be employed for operating the draft doors of both the gas combustion chambers and the ash p it.

When no coal is being burned, I prefer to disconnect the chain 3|, so that the draft door 29 will remain closed, and draft be had only through the draft doors 36. However, when coal is being burned, there Will be an advantage in having both the draft doors 36 and 29 open, since air will iloW through the spaces 40 and become heated by the re bricks 2l, thereafter entering into the upper portion of the re box Where it will assist in eiecting more perfect combustion of the volatile products from the coal.

Referring now to Fig; 6, the partition walls 22 may be provided with openings 43 that may [be opened and closed by suitable slides 44. In somecases, it may be desired to deflect some of the gas`v heat through the ire box in which case the slides to the burners 3l. Y

I claim as my inventionzl. Heating apparatus comprising a lire-box casing` of generally rectangular formand having an opening in the lower portion of its front wall, rearwardly-extending partition walls in thelower part of the casing, adjacent to but spaced from the side walls thereof and having channels formed along lines adjacent tol their upper edges, refractory slabs supported upon the uppermost sides of said channels, in spaced relation to the adjacent side walls of the casing and serving to form the sides of a fuel-burning space which communicates, at the tops of the s1abs,with the spaces at the outer sides of the slabs, grate bars having Ytheir ends'supportedV in said channels and being slidably removable from the front ends of Y the channels, and a removable face plate cover ing the said opening in the front wall of the casing and the front ends of the channels, the spaces between the outer sides of the slabs and the side Walls of the casing being provided With openings near their lower ends, for the admission of additional air for combustion.

2.` Heating apparatus comprising a lire-box casing of generally rectangular form and having an opening in the lower portion of its front Wall, rearwardly-extending partition Walls in the lower part of the casing, adjacent to but spaced from the side walls thereof and having channels formed along lines adjacent to their upper edges, re-

fractory slabs supported upon the uppermost sidesY of'said channels, in spaced relation to' the adjacent sidewalls of the casing and serving to form l the sidesof a fuelfburning space which communicates, at the tops of the slabs, with the spaces at the outer sides of the slabs, vertical anges on the upper sides of the channels, which, engage innervertical faces of the slabs and prevent;

movement of the slabs away from the side walls,

of the casing, grate bars having their ends supported in said channels. and being slidablyr re-4 

